This invention relates to fan propulsors of the type where the fan (either fixed or variable) is enclosed in an engine bypass duct and is closely coupled to a gas turbine engine and particularly to means for preventing blade oil leakage from migrating to the inlet of the engine.
It is known that oil ingested in the engine not only may be the cause of loss of engine efficiency with possible deterioration of combustion but also oil in the compressor airstream could migrate into the bleed air system with possible carry over in the air conditioning system where it could contaminate the aircraft cabin and the like. This invention is particularly concerned with a ducted fan propulsor where the engine is closely coupled to the fan, since such an environment increases the potential of this occurrence. While in the past the leakage of oil directly in the airstream was acceptable, it is intolerable for a ducted fan application. Thus, a single seal for the fan blade seal would by itself be unacceptable.
This invention obviates the problem noted above by providing capturing and venting means of oil leaking from the blade seal, without adding to the blade/hub complexity by using double sealing techniques or redundant devices or the like.